1. Field of the Invention
The present invention relates to a pipe joint.
2. Description of the Related Art
A previously known pipe joint comprises two sealing surfaces provided at separate end portions of two pipes, the sealing surfaces being adapted to be axially forced together to a position in which one of the sealing surfaces encloses the other sealing surface for constituting the pipe joint. Thereby, the sealing surfaces form a substantially cylindrical or somewhat conical sealing space. The pipe joint also comprises a sealing device which after the sealing surfaces have been forced together is positioned in said sealing space. The sealing device comprises a sealing ring which before the sealing surfaces are forced together is positioned axially indisplaceable in relation to one of the sealing surfaces and is compressed between the sealing surfaces while the sealing surfaces are forced together, the sealing ring thereby being axially displaced in relation to the other sealing surface.
Pipe joints of this kind are previously known from for example the Swedish patent specifications Nos. 7809451-3 and 8105254-0. The pipe joints shown and described in these patent specifications comprise a sealing ring consisting of rubber or rubber-elastic material which is positioned at the inner surface of a concrete pipe socket. The sealing ring has a main body and a fastening portion manufactured unitarily therewith and moulded into the pipe material. The inner surface of the pipe socket forming the sealing surface thereof has axially outside the sealing ring a portion of less diameter than the portion positioned axially inside the sealing ring. This difference of the diameters provides an undercut space positioned inside the sealing ring, in which space the main body of the sealing ring can be partially received at the compression thereof taking place when the pipe joint is provided, i.e. when the main body is compressed between the sealing surface of the socket and the sealing surface formed by the outer surface of the spigot end introduced into the socket.
A drawback of pipe joints of the kind described above is insufficient properties with regard to the capacity of taking up and standing transverse loads, i.e. such loads on the pipes causing the pipe end portions forming the pipe joint to be displaced from a concentric towards an eccentric position. Thus, the transverse loads provide that the sealing surfaces are locally displaced towards each other to a position in which the sealing surfaces locally engages each other and/or the sealing ring is locally subjected to a compression of such a magnitude that the transverse loads are balanced.